Akos Lakatos

• Professor
• University of Debrecen

Most power plants and district heating systems employ rock wool or ceramic fiberglass insulations to insulate their pipes. Over time, these materials lose some qualities. The present study tested two thermal insulation materials for applications in pipelines carrying hot steam in power plants or district heating (DH) systems: ceramic fiberglass (in...

This study investigates the hygrothermal performance of wood-frame walls in the Baltic region under varying moisture loads, comparing bio-based and conventional insulation materials. The research combines experimental climate chamber testing with DELPHIN simulations to assess moisture risk mitigation, energy efficiency and mould growth resistance....

The main topic of the paper is to investigate the thermal examination of aerogels and their vacu-umed forms, application possibilities, and environmental impact. In the paper, the thermal conductivity of homemade vacuum insulation panels was tested with different silica-based core materials. Three types of fibrous aerogel materials were used as cor...

New buildings are subject to more stringent regulations that focus on reducing inefficient energy consumption and eliminating associated harmful emissions. This challenge has been exacerbated by the current energy crisis. As a result, there has been an increase in the development of energy-efficient and environmentally friendly design strategies, t...

Nowadays, if one wants to renovate or build a building, the question of thermal insulation is an essential construction process. Polyurethane is a key thermal insulation material that belongs to plastic foams. It can be applied as a spread or board heat-insulating material. Its thermal insulation properties are superior compared to polystyrene, but...

Lightweight materials such as microfiber insulation or polymer foam are typically used to insulate cars and aircraft. But here, too, the use of state-of-the-art “super-insulating” materials is a valid answer. Vacuum insulation panels also serve as reliable insulators for electric vehicles. In this study, we will analyze in depth the potential uses...

The applications of insulation materials in buildings and vehicles are more important than ever. Therefore, the application of thermal insulation materials having high-performance heat-blocking properties such as nano-structured insulations like aerogels and graphite polystyrene is essential. In this paper a comprehensive thermal characterization w...

Using thermal insulation materials to reduce energy loss in buildings is a key action. For reducing the building’s energy use, firstly, the internal unheated spaces (attics, cellars) should be insulated, followed by the insulation of the external walls, and changing the doors and windows. Finally, the building can be completed with the renovation/m...

For thermal insulating vehicles usually, lightweight materials are used, such as polymeric foams or microfiber insulations. But, the use of novel so-called super insulation materials can also be a good solution for this. Vacuum insulation panels can be reliable insulators for electric vehicles, too. In the paper, we will give a comprehensive review...

Nowadays, to improve quality of life, to have a more comfortable life, in internal spaces we try to maintain conditions that are free from external environmental influences. Thus, existing as well as newly built houses have adequate interiors maintaining their temperature, warming, or cooling due to the environment compensation. One way to create t...

The main purpose of this paper is to present the use of super thermal insulation materials for a historical building through a calculation-based case study. The development of the insulation materials is based on the objective of making buildings as energy efficient as possible, and the energy loss should be kept to a minimum, for both new and exis...

From the beginning, the buildings have been tasked with protecting man from the external environmental impacts. Technological development has brought with its buildings and building structures development. Nowadays, the expectation is that in the interior of buildings it is for man to ensure a comfortable environment at all times of the year. Exter...

Decreasing the energy loss both by buildings and by vehicles perhaps one of the most important efforts to protect our environment and energy resources. An option to achieve this is to apply thermal insula�tions moreover, of super insulation materials (such as aerogel) are becoming increasingly justified. How�ever, these are relatively new material...

Featured Application This paper contains laboratory measurements of four different micro-fiber thermal insulation materials to reveal their applicability limits under various environmental conditions. On the samples, scanning electron microscope investigations were executed to disclose the structure of the fibers. The study also investigated the mo...

Decreasing the energy loss both by buildings and by vehicles perhaps one of the most important efforts to protect our environment and energy resources. An option to achieve this is to apply thermal insulations moreover, of super insulation materials (such as aerogel) are becoming increasingly justified. However, these are relatively new materials....

For reducing the energy use of buildings, the application of insulation materials can be a possible solution to improve energy efficiency. However, with the continuously tightening regulations, thicker and thicker insulations should be used (e.g., up to 20-25 cm in Hungary and about 40-50 cm in the Nordic countries) to fulfil the directives. In the...

Featured Application This paper complements previous research studies executed on fiber-reinforced aerogel insulation. Here, we show that laboratory experiments executed on materials in order to see the environmentally affected changes of their thermal properties should be completed with calculations to see the application limits of the materials i...

Buildings account for almost 40 % of total energy use, in the European Union. Energy losses in this sector should be reduced. To achieve this, thermal insulation of buildings is one of the possibilities. The potential for energy savings can be increased by retrofitting buildings with insulation. In order to sufficiently reduce the heat loss through...

Nowadays, the usage of thermal insulation materials is widespread not only in the building sector but also in the vehicle industry. The application of fibrous or loose-fill insulation materials like glass wool or mineral wool as well as aerogel is well known. Aerogel-based materials are among the best solid materials for thermal insulation availabl...

Insulation materials are mainly porous or fibrous materials. Therefore, the presence of moisture can easily cause problems inside the materials, and in the whole building structure. For correct calculations of heat and moisture transfer problems in building applications, practitioners need design values. Design thermal values are deduced and calcul...

In this paper a laboratory test completed with caclulations will be presented in order the designate a possible material to be used as an insulation for a pipe system. Four different types of insulation materials (fibrous aerogel, mineral wool, armaflex and polyurethane) will be tested. Once their thermal conductivity will be measured with a Holome...

Nowadays, aerogel materials are some of the lightest thermal insulation materials available on the construction market; they are produced by the mixing of polymers with solvents since they create a gel. Insulated fibrous-enhanced forms are the most frequently used ones. The type, which is used for thermal insulation, is usually produced by mixing t...

Deadline for submission: 20 September 2019 This Special Issue aims at providing recent developments in laboratory analyses, computational modeling and in situ measurements related to the assessment of building energy performance based on the proper identification of heat and mass transfer processes in building structures. Potential topics include...

Nowadays, the application of thermal insulation materials both by the existing and by new buildings is one of the most important actions in order to reduce the energy loss of buildings. Besides the use of the conventional insulations (plastic foams and wool materials) aerogel is one of the most promising thermal insulation material. Aerogels, one o...

These days the use of the traditional (conventional) insulation materials requires greater thicknesses (e.g. up to 25 cm) in order to reach significant reduction in the heat loss and in the emission of the greenhouse gases. In some cases the use of these thicknesses cannot be implemented. In the last decade, a new direction was designated in order...

Nowadays, besides the use of conventional insulations (plastic foams and wool materials), aerogels are one of the most promising thermal insulation materials. As one of the lightest solid materials available today, aerogels are manufactured through the combination of a polymer with a solvent, forming a gel. For buildings, the fiber-reinforced types...

The use of silica aerogel-enhanced blankets as a thermal insulation material is one of the most promising solutions to reduce the heat loss through the building envelope. Aerogel-enhanced blankets provide exceptionally high thermal resistance, thanks to a thermal conductivity value as low as 0.014 W/mK. However, a challenge in the use of aerogel-en...

Nowadays fibre reinforced silica aerogels receive special attention due to their application in the building construction sector. Aerogel, besides the Vacuum Insulation Panels are one of the so-called super/advanced/nano-technological insulation materials due to their low declared thermal conductivity. However, these days their high manufacturing c...

in the effective thermal conductivity. Besides the use of conventional insulating materials, such as mineral fi bers, the adoption of new nano-technological materials such as aerogel, vacuum insulation panels, graphite expanded polystyrene, is growing. In order to reduce the thermal conductivity of polystyrene insulation materials, during the manuf...

Nowadays fibre reinforced silica aerogels receive special attention due to their application in the building construction sector. Aerogel, besides the Vacuum Insulation Panels are one of the so-called super/advanced/nano-technological insulation materials due to their low declared thermal conductivity. However, these days their high manufacturing c...

In this article laboratory measurements will be presented in order to show the effect of the temperature difference in the thermal resistance of an insulated wall. Insulation of buildings is key action to reduce the energy use of buildings as well as to reduce the emission of green house gases. Laboratory measurements with calibrated chamber method...

Nowadays, the thermal insulation both of existing and new buildings is one of the most important actions for reducing the energy loss of buildings and to reduce the emission of green house gases. In the European Union, buildings account for about 20–40% of the total final energy consumption. Examination of the thermal properties (e.g., effective th...

In the literature, several definitions can be found for the thermal conductivity; however, many of them are not clearly explained. The easiest explanation is the following: the property of a material to conduct heat. It is evaluated primarily in terms of Fourier’s Law for heat conduction. Nowadays, the examination of the thermal conductivity of bui...

Nowadays, to sufficiently reduce the heat loss through the wall structures with the so-called traditional insulations (polystyrene and fibrous slabs), huge thicknesses (20 – 25 cm) must be applied. In some cases there is no place for their applications e.g.: historical or heritage builfings, since the use of nano-insulation materials (aerogel, vacu...

The laboratory investigations of the heat transfer properties of wall structures are very significant from the point of view of designing the buildings. In this article measurements and calculations will be presented in order to manifest the effect of the forced and un-forced convection of air at the cold surface of the wall. A steady-state method...

Nowadays to reduce the energy loss as well as to minimize the emission of the green house gases of buildings can be solved by thermal insulating. Silica aerogels have a promising potential in the building and construction sector as thermal insulation due to their excellent thermal conductivity. At the present time the applications of silica aerogel...

Buildings in Europe, account for about 20–40% of total final energy consumption. Therefore reduction of energy demand is crucial. It has become one of the most important issues to achieve energy saving at installations and refurbishments of buildings. Humidity in the wall structure of buildings produced by precipitate and other circumstances could...

During the thermal assessment of buildings, proper understanding and knowledge of the thermal behavior of the materials is required. Certain indoor and outdoor conditions can cause moisture transfer and could change the thermal properties of buildings (e.g. thermal conductivity, resistance, thermal diffusivity, specific heat capacity, etc.). In thi...

Nowadays, energy saving as well as energy-conscious design and refurbishments of buildings became the most important actions to be achieved worldwide. The energy performance of a building can be considerably affected by climate. The significance of a ‘design with climate’ approach is highlighted in this paper. The article investigates the impact of...

Ahhoz, hogy kellő mértékben csökkentsük a falakon keresz-tüli hőveszteséget a hagyományos szigetelőanyagokat (poli-sztirol, gyapottáblák) ma már nagy méretekben kell alkalmazni (20-25 cm). Bizonyos helyeken ez a vastagság nem alkalmaz-ható (műemlékvédelem, telekhatár stb.), ezért a nanotechno-lógiás hőszigetelő anyagok (aerogél, kerámia tartalmú hő...

Ebben a cikkben be szeretnénk mutatni, hogy Magyarország és vele két szomszédos ország (Románia és Horvátország) fővárosainak éghajlati adatai mennyire befolyásolják ugyan-azon épület fűtési energiaszükségletét, amellett, hogy a külső homlokzatát még nedvesség (magas párataralom, csapóeső) is terheli. A vizsgálatainkat egy hipotetikus, szokványos p...

These days, the thermal insulation of existing and new buildings is one of the most important actions for reducing the energy loss of buildings and to reduce the emission of green house gases. The Directive of the Energy Performance of Buildings defines the energy performance of a building as the energy needed to meet the energy demand associated w...

As it is well known, thermal insulating of buildings is one of the most important methods to reduce the energy loss of buildings and to reduce the emission of green house gases. This paper studies the conductive heat transfer in silica aerogel, moreover, through a wall structure covered with this insulator. Aerogels are nanoporous lightweight mater...

This article reviews and highlights the comparison between different insulation materials and their thermal properties used for food science, transporting, and packaging. Heat and mass transfer values are necessary for engineers and fabricators to design appropriate environments for food storage and refrigerated transport. To preserve the value of...

This paper highlights wetting measurements and results carried out on four different generally used construction and some insulating materials, executed in our Building Physics laboratory in University of Debrecen, Faculty of Engineering, Debrecen, Hungary. The measurements focused on the initial state of the water up-takin procedure (240 min wetti...

In recent years measurements and calculations of the thermal properties of building physics parameters of materials have become very important for thermal sizing and designing buildings. Moisture is an essential factor to consider when designing and applying building materials. This article investigates the influence of moisture in building physica...

Recently, it has become extremely important to reduce the heating energy demand and the CO2 emission of buildings. This reduction can easily be achieved by insulating the shell of buildings. By thermal insulation not only the heating energy demand can be reduced but also higher thermal efficiency can be reached. Therefore, measurements, calculation...

The thermal and water insulation of buildings is extremely important. Currently, the most applied insulation materials in the building sector are plastic foams and fibrous materials. Different types of polystyrene materials are used as water and thermal insulators, e.g., expanded polystyrene (EPS) and extruded polystyrene (XPS). The differences bet...

Currently, thermal insulation of buildings is required from both an energy savings perspective and a money savings perspective. Insulation is primarily installed on the outer surface of the buildings. Weather and other circumstances can produce humidity that can act on the building structure, e.g., by changing its heat capacity, the heat transfer c...

In all European countries the energy and building related legislature stand for energy refurbishment of existing building stock. Depending on the economical situation of countries there are different national programs that help owners to invest in energy related refurbishments of their houses or flats. The financial support is given only in case of...

In this paper we present measurements and measurement methods carried out on construction and building materials in our Building Physics laboratory in University of Debrecen, Faculty of Engineering, Hungary. The investigations with different methods are so significant from the point of view of thermal sizing and designing of the buildings. The labo...

Currently thermal insulating of the buildings is sorely needed from the point of view of energy as well as money savings. Isolations are mostly installed on the outer surface of the buildings. Weather and other circumstances can produce humidity that can affect the building structure by changing its heat capacity and heat transfer value and other f...

Currently thermal insulating of the buildings is sorely needed from the point of view of energy as well as money savings. It is important to highlight that the most commonly used insulation materials in the building sector are the expanded polystyrene (EPS), the extruded polystyrene (XPS) and the fibrous (mineral, rock) ones. In this communication...

In this paper the analysis of the shape of the sorption isotherm curves of different materials that were carried out from the result of measurement is presented. The investigation of the behaviour of the construction and building materials against water and humidity is highly important from the point of view of thermal sizing of the buildings. Sinc...

As it is known that nowadays, reduction of the heating energy loss of buildings is achieved mainly by thermal insulation. This is one of the most important objectives of buildings constructions and retrofitting of buildings. Therefore research, calculation and simulation on the energy efficiency of buildings are of great importance. In this paper w...

These days, the investigations of the physical properties of the insulating materials are very important. In this paper we report the measured water uptaking capabilities of a thermal insulating paint. They can be found in liquid phase, but we measured dried solid samples. The thin thermal insulators (insulator coatings) are starting to spread on t...

Nowadays, the most applied insulation material in the building sector is the expanded polystyrene. Different types of expanded polystyrene are used but more widely used is the graphite added type. Our research focuses on the analysis of heat conductivity and sorption properties of expanded polystyrene as these two are the most important physical pr...

This article presents the results of water sorption properties investigation and thermal conductivity measurements of expanded polystyrene thermal insulation materials with different mass densities. The sorption behaviour of the expanded polystyrene materials was achieved in a Climacell 111 type climatic chamber, after drying in a Venticell 111 typ...

The thermal insulating of the buildings is so important from the point of view of reducing the heat losses, and to prevent the building envelope from the outer effects. The 2020 directive of the European Union predicts very low U-values for the low-energy, or nearly passive houses (pl.: U: 0,1-0,15 W/m2K). This value is in the same range like the t...

Analysis of thermal conductivity of different insulation materials is very important in applications for passive and nearly zero houses. This paper presents the measurements results of the thermal conductivities of expanded polystyrene (EPS) insulation materials, with different thicknesses and air pore content. The measurements were achieved on pur...

TÁMOP-4.2.2.A-11/1/KONV-2012-0041

Mass transport and solid-state reactions in nanocrystalline thin films are reviewed. It is illustrated that diffusion along different grain boundaries (GBs) can have important effects on the overall intermixing process between two pure films. These processes can be well characterized by a bimodal GB network, with different (fast and slow) diffusivi...

Low temperature analysis of diffusion and intermixing of Co–Si systems are very important in applications for microelectronics and Ultra Large Scale Integration (ULSI). In this communication a comprehensive report has been given on degradation and diffusion processes in the Si(substrate)/Co(150 nm)/Ta(10 nm) system. The samples were prepared by DC...

CONF_NAME: Building Services, Mechanical and Building Industry days, International Conference, CONF_NUMBER: (18), CONF_DATE(2012), CONF_PLACE: (Debrecen)

Proper understanding of sorption behaviour of the materials is important from the point of view of fundamental research and technology as well for applied building technology. In this paper a simple method is presented for measuring water sorption capability of solid bodies. Moisture sorption and desorption measurements were carried out on soil sam...

It was shown more recently in our Laboratory [1,2,3] that having a substrate/diffusant/thin-film/cap-layer structure (the thin film was typically several 10 nm thick, with the same order of magnitude of grain size; the refractory metal cap layer was used just to avoid the oxidation), first the diffusant atoms migrated very fast across the thin film...

CONF_NAME: Building Services, Mechanical and Building Industry Days, CONF_NUMBER: (17), CONF_DATE(2011), CONF_PLACE: (Debrecen)

We describe a method for measurement of nanoscale shift of interfaces in layered systems by a combination of secondary neutral mass spectrometry and profilometer. We demonstrate it by the example of the investigation of interface shifts during the solid state reaction in Ni/amorphous-Si system. The kinetics of the shrinkage of the initial nanocryst...

Proper understanding of the degradation mechanisms and diffusion kinetics of copper and cobalt interconnections for advanced microelectronics is important from the point of view of fundamental research and technology as well. In this paper Si(substrate)/Ta(10nm)/Cu(25nm)/W(10nm) and Si(substrate)/Co(150nm)/Ta(10nm) samples, prepared by DC magnetron...

Proper understanding of the degradation mechanisms and diffusion kinetics of copper and cobalt interconnections for advanced microelectronics is important from the point of view of fundamental research and technology as well. In this paper Si(substrate)/Ta(10 nm)/Cu(25 nm)/W(10 nm) and Si(substrate)/Co(150 nm)/Ta(10 nm) samples, prepared by DC magn...

One of the most important processes in Cu metallization for highly integrated circuits is to fabricate reliable diffusion barriers. Recently, thin films made of refractory metals and their compounds have been widely used in solid-state electronics as barriers because of their good electric properties, favourable thermal properties and chemical stab...

CONF_NAME: International Workshop Diffusion and Solid State Reactions on Nanoscale, CONF_PLACE: Debrecen, Magyarország

CONF_NAME: Book of abstracts of 4-th Symposium on Vacuum based Science and Technology in conjunction with 8-th Annual Meeting of German Vacuum Society., CONF_PLACE: Kolobrzeg, Lengyelország

Copper is widely used interconnect mate-rial as a replacement of aluminum in semicon-ductor devices because of its high electricalconductivity and electromigration resistance.The most important life-time limiting processin devices is diffusion between semiconductorand interconnects layers. It was an early ob-servation that Cu can easily migrate to...